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THE TOUQUES RIVER BASIN, an outstanding example of river restoration

The announcement of a national action plan to restore the ecological continuity of rivers was made in the Touques river basin in Normandy, itself an excellent example of restored continuity. Over the past 30 years, thanks to the work done and the efforts of many participants, the Touques basin has become fully accessible for migratory fish.

In 1978, in the framework of the first Salmon plan launched by the Ecology ministry, a study on sea trout revealed the great potential of the Touques river basin. The size of the spawning grounds and the proximity to the ocean contributed to abundant numbers of this migrating variety of brown trout. However, only 15% of the basin's potential was realised due to the many obstacles blocking migratory fish. These initial results produced initial efforts and, over the next 30 years, numerous initiatives were taken by local players and State services to restore access to the rivers in the basin.

During the 1980s, the Calvados fishing federation and Onema (then CSP) created the first fishways and initial maintenance work on river banks was launched. Ten years later, efforts to restore travel of fish increased significantly. Onema and DDAF (Agricultural and Forestry agency) worked on a number of technical projects to support local partners. Work dealt primarily with river hydromorphology and the elimination of unused structures. In 1999, a fishway was built for the Breuil-en-Auge dam, the major obstacle on the Touques river, thus doubling the area open to sea trout.

Improvements in the lower part of the basin took a great step forward in 2004 with the inauguration of the new wastewater-treatment plant for Lisieux, the largest town in the river basin. Reinforcing the above work was a legal framework in favour of migratory fish that was extended to the entire river basin in 1999 and the creation of the Touques river board in 2007, whose mission is to restore and maintain the local rivers, paying particular attention to the fishways.
Over 30 years, 71 obstacles spanning 200 kilometres were modified, increasing the area open to sea trout from 15% in 1982 to 86% in 2009. Today, the annual stock of sea trout in the Touques river basin numbers approximately 10 000, making it the number one river in France for sea trout and one of the best in all of Europe.

Contact: arnaud.richard@onema.fr

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